1. Field of the Invention
The present invention relates to an image reader for reading an image recorded on a transparency of a photographic film or the like.
2. Description of the Related Art
An image reader employing an imaging device of a CCD and so forth is used for photoelectrically reading an image recorded on a transparency of a photographic film or the like. Image processing of scaling, correction processing and so forth are executed on image data obtained by the image reader. On the basis of the processed image data, an image is formed on a recording material.
In the image reader, pre-scanning and fine scanning are performed. During the pre-scanning, the image is preliminarily read for the purpose of reading the image with accuracy. During the fine scanning, the image is read under read conditions determined in accordance with density of the image.
As to a light source employed in the image reader, a conventional halogen lamp is used. Beside the halogen lamp, a light source in which LED elements are arranged is used. The LED elements emit the light of each color of red, green and blue. By employing the light source constituted of the LED elements, the device itself may be downsized. Further, there is an advantage that the lifetime of the light source is prolonged in comparison with the case of the halogen lamp.
However, when the light source constituted of the LED elements is used, mechanical performance thereof disperses in comparison with the case of the halogen lamp. Due to this, in some of the light sources, accuracy of reading the image deteriorates and readout time becomes long. Meanwhile, it is considered that a light amount of the light source is regulated by means of a volume such as a conventional analog printer employing the halogen lamp. In this case, however, it is necessary for the light source constituted of the LED elements to provide a plurality of volumes relative to the respective colors. In addition, it is also necessary to individually adjust the volumes. Thus, there arises a problem in that adjusting the volumes is troublesome.